I'm currently figuring out what work needs doing to our two server cupboards over the summer. The idea is that we have two cupboards, in separate wings of the school, so if something diasaterous happens to one then the other is left to keep running. This only works up to a point at the moment - the second server cupboard has no cooling and tends to get good and toasty, and the UPS didn't handle testing so well today ("Power's off, is stuff still running?", "No.", "Bother.").
I have environment monitoring sorted out - simply a PC with a temperature sensor and UPS-monitoring cable plugged in. It's set to turn itself off if running on battery for more than a minute or if the temperature gets too high, then I plan to have another PC monitoring that.
The UPS currently in use is an APC Smart-UPS 750. Simply switching the power off to it made the two machines attached to it fail, which makes it a bit pointless. Is that failure maybe just due to an aged bettery, or is there possibly a different brand of UPS that people would recommend?
It will likely be the batteries. They look all nice and charged until you actually try to use them and they say not today thank you!
The monitoring software (APC's PowerChute Business Edition, monitoring the UPS via serial as USB failed to work for some reason) says the UPS has 23 minutes runtime left, however actual runtime is 0 (cut the power, everything stops). With the failed USB and dodgy readouts I'm inclined to get a whole new UPS - I don't want to get new batteries to find that the UPS still doesn't work reliably.
We have an identical setup which I'm currently working on, responses will be interesting. I'd like a small air-con unit and UPS for the second cupboard, but may be a bit pushed!
The cheap-as-possible temperature sensor from eBay is currently reporting a temperature of 31C - I've just borrowed a thermometer from science to double-check that's accurate. I'm guessing it's got a lot hotter in there in the past, though - there's only one server running in there now as the other one packed up, I think from overheating. I was maybe thinking of a floor-standing air conditioner capable of a "ton" of cooling (1200 BTUs, I think) - around £500 from Argos, which seems pretty resonable for an all-in-one, drop-in solution.
With the failed USB and dodgy readouts I'm inclined to get a whole new UPS - I don't want to get new batteries to find that the UPS still doesn't work reliably.
It'll require some downtime, but does the other UPS use the same batteries? It's a cheap test if it does - swap them for a test and give it a dummy load (stuff without data on) and see how well it fares.
A smartUPS 750 is quite small for a two PC load let alone a two server one, it is probably the batteries but it could also very well be pulling too much current for the unit itself to supply when on battery power. I would be looking at a 1500 for a couple of machines just to give it the overhead, this should also give you longer runtimes for the servers in the case of a short powercut or something simmilar.
A smartUPS 750 is quite small for a two PC load let alone a two server one
Good point - I think we're going to be maybe looking at the 2200. The cupboard will have at least four machines running in it: mirroring VM server, backup file server, video file server and environment monitoring PC, plus a network switch. Power only has to last long enough for the monitoring software to register the fact and gracefully shut everything down, so 5 to 10 minutes should be fine.
It will give you a good idea of what to buy load wise . We use r5000va on all of our server cupboards(most have 5 or more server +switches, etc) and they are excellent.Comes with temp. shutdown and web interfaced software. Always worth checking the load rate on the ups ,most of the larger units require a 30amp supply and you should have a clean earth on the cab.
if we can help you out in quoting for the UPS please do let me know.
I'm trying to figure out what sort of size of UPS we're likly to be looking at, first. I think our second server cupboard is likly to wind up containing a server running a bunch of virtual machines, a large (12 SATA disks) file server and a smaller (4 SATA disks) file server. It will also contain a PC set up to monitor power and temperature, and there's a 16-port network switch, but those can run off a Back-UPS 350. Some room for future expansion would probably be a good idea. How much power are those three servers, some with lots of disks, likely to draw? Do I allow 1KW each for them, or is that being a bit excessive? What UPSes do you sell - just APC, or can you particularly recommend another brand?
Last edited by dhicks; 17th June 2010 at 10:10 AM.
I'd then double what you come up with for overhead and future expantion and aim for that. Most hardware will have current draw specs and if not just make an estimate on the generous side for the device. This is easier with some equipment from major manufacturers as there is are lots of load calculators that will help size the ups as have been suggested before.